Quick-release bolt for use with pump housing

ABSTRACT

A quick release bolt for securing two or more parts together is disclosed. The quick-release bolt includes a threaded end and a slotted end opposite the threaded end. The slotted end includes a slot extending across a diameter of the bolt and extending axially into the bolt. A release/lock plate is pivotally attached to the bolt within the slot in the bolt by a pin that is attached to the bolt. The pin extends transversely through the slot in the bolt and passes through a slot in the release/lock plate. The release/lock plate may be pivoted between locking and releasing positions when the bolt is loosened only about one-half to one-quarter of a turn from a tightened position.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. application Ser. No. 08/525,394 filedSep. 8, 1995, now U.S. Pat. No. 5,630,711.

TECHNICAL FIELD

The present invention relates to fluid pumps in general, and morespecifically to peristaltic pumps.

BACKGROUND ART

Peristaltic pumps are well-known devices which transfer fluid through anelongate flexible tube by compressing a portion of the tube, and pushingthe fluid through the tube using such compression. Peristaltic pumps;are commonly used for transferring fluids such as ink for printing orfor transferring fluids such as blood in medical equipment. Peristalticpumps may also be used to transfer fluids such as cleaning agents,coolants, slurries or liquid adhesives, just to name a few of the manyfluids that can be transferred with such pumps. One advantageous featureof peristaltic pumps is that the fluid does not contact the pumpmechanism since the fluid is always confined within and moved throughthe flexible tube. Therefore, peristaltic pumps may be used to transfercorrosive or caustic solutions or other hazardous fluids withoutaffecting the pump mechanism.

In a typical peristaltic pump, the tube is compressed by one or morerollers that are driven by an electric or air-powered motor. Each rollercompresses the tube as it moves along the length of the tube. Alsotypically, the flexible tube is fed through the pump along a generallyU-shaped path or alternatively along a substantially straight arc-shapedpath (in the case of a pass-through pump) so that the U-shaped orarc-shaped portion of the tube overlaps a portion of a path traveled bythe rollers. Such arrangements have numerous disadvantages. For example,the tube can undesirably creep through the pump during operation. of thepump, requiring either periodic adjustment of the tube, or a separateclamping device to prevent such creep of the tube. A U-shaped orsubstantially straight arc-shaped tube path in a peristaltic pumpprovides a small contact area between the pump rollers and the tube, asthe rollers are only in contact with the tube over a small portion ofthe overall path of travel of the rollers. As a result, depending on theflow rate requirements imposed on the pump, there can be substantialfatigue imposed on the tube. The use of additional rollers may partiallycorrect this problem, but causes additional wear on the tube and addscost and complexity to the pump.

In many peristaltic pumps using a U-shaped tube path, the flexible tubeis oriented such that the fluid flowing into the pump flows in adirection opposite to that of the fluid flowing out of the pump. In suchan arrangement, additional space and tube length is required if the pumpis to be disposed along a line leading from the source of fluid directlyto the destination to which the fluid is being pumped, as the tube mustturn 90° to enter the pump and the tube must also turn 90° to exit thepump. As will be appreciated, these turns could also cause kinking ofthe flexible tube that would either interrupt or at least interfere withthe free flow of fluid. Such kinking is highly undesirable and could bedangerous in some applications.

The housing of a typical peristaltic pump as well as: the componentslocated within the housing can be complex and expensive to manufacture,especially if a large number of rollers are used in the pump. Therefore,there is a need for a peristaltic pump that is economical tomanufacture, durable, compact and capable of reliably and efficientlypumping fluid.

SUMMARY OF THE INVENTION

In accordance with the present invention, a housing for a peristalticpump is provided, having an inlet port, an outlet port and a loop-shapedtube path within the housing. Preferably the loop-shaped tube pathincludes means for orienting a flexible tube to have parallel portionsbetween the inlet port and the outlet port. Also preferably, the tubeorienting means includes a crescent-shaped guide block located in theinterior of the housing generally intermediate the inlet port and theoutlet port.

In an exemplary embodiment, the loop-shaped tube path is defined by asubstantially circular wall portion of the interior of the housing thatcauses the flexible tube to be disposed in a complete loop within thehousing. An outwardly facing surface of the guide block defines a tubepath segment which comprises a first perimeter portion of theloop-shaped tube path. A second perimeter portion of the loop-shapedtube path is defined by the substantially circular wall portion that isperimetrically spaced from the first perimeter portion of theloop-shaped tube path. The first perimeter portion of the loop-shapedtube path may be disposed radially outwardly of the second perimeterportion of the loop-shaped tube path such that the tube path isgenerally elliptical.

In the preferred embodiment, the inlet port and the outlet port areoppositely facing along parallel axes generally tangential to theloop-shaped tube path. In addition, the housing preferably comprises apair of identical housing halves, made from a translucent or opaquematerial such as LEXAN® polycarbonate material, available from theGeneral Electric Company, 3135 Easton Turnpike, Fairfield, Conn. 06431.

According to another aspect of the present invention, a peristaltic pumpfor moving a fluid through a flexible tube comprises a housing, a maindrive shaft mounted for rotation within the housing, and a rotor drivenby the main drive shaft within the housing. At least one roller shaft isattached to the rotor and a roller is rotatably mounted on each rollershaft. The housing includes an inlet port, an outlet port, and aloop-shaped tube path joining the inlet port to the outlet port andgenerally surrounding a circular rotational path of the roller orrollers.

The peristaltic pump constructed in accordance with the presentinvention provides a compact, efficient, and durable mechanism fortransferring fluid through a flexible tube. The loop-shaped tube pathprovides roller contact with the tube over a large portion of the rollerpath, thereby permitting the use of only two rollers and minimizing wearon the tube. The loop-shaped tube path also allows the pump to bedisposed between a fluid source and a fluid destination along asubstantially straight line, while minimizing space, tube lengthrequirements, and the possibility of tube kinking. In addition, theparallel portions of the tube are pressed against one another so as tobe in frictional contact within the housing thereby reducing oreliminating the tendency of the tube to creep through the housing.

Other advantages and features of the present invention will becomeapparent from a consideration of the following specification taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a peristaltic pump constructed inaccordance with the present invention;

FIG. 2 is an inverted front elevational view of the peristaltic pump ofFIG. 1;

FIG. 3 is a rotated side elevational view of a half of a housing for theperistaltic pump of FIG. 1;

FIG. 4 is an exploded perspective view illustrating components of theperistaltic pump of FIG. 1;

FIG. 5 is a perspective view illustrating the exterior of the housinghalf shown in FIG. 3;

FIG. 6 is a perspective view illustrating the interior of the housinghalf of FIG. 3;

FIG. 7 is a perspective view illustrating the components shown in FIG.4, in an assembled state;

FIG. 8 is an elevational view showing the interior of the housing halfof FIG. 3 with a flexible tube installed therein;

FIG. 9 is an elevational view of the interior of the housing half ofFIG. 3 with a flexible tube installed therein and showing the componentsof FIG. 7 installed therein;

FIG. 10 is an elevational view of a quick release attachment bolt forthe peristaltic pump of FIG. 1, shown in a locking configuration;

FIG. 11 is an elevational view of the quick release attachment bolt ofFIG. 10, shown in a releasing configuration; and

FIG. 12 is an elevational view taken along line 1212 of FIG. 10.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Initially referring to FIG. 1, a peristaltic pump, shown generally at20, comprises a motor 22 that rotates a drive shaft 24 disposed betweenthe motor 22 and a pump housing shown generally at 26. The motor 22 isof a conventional design and may be, for example, electrically driven orpneumatically driven. The pump housing 26 comprises first and secondidentical housing halves 28, 30 that form an inlet port 32 and an outletport 34 (not shown in FIG. 1). The housing halves 28, 30 are preferablytranslucent so that operation of the peristaltic pump 20 may be visuallymonitored. Preferably, each of the housing halves 28, 30 are constructedof LEXAN® polycarbonate material.

As best seen in FIG. 6, each of the housing halves 28, 30 includes threeguide posts 29 and three guide holes 31. The guide posts 29 and guideholes 31 on the first housing half 28 mate with the corresponding guideholes 31 and guide posts 29, respectively, on the second housing half30. Thus, the guide posts 29 and guide holes 31 serve to ensure properalignment when the housing halves are joined together to form thehousing 26.

Again referring to FIG. 1, each housing half 28, 30 includes lugs 36through which quick release attachment bolts 37 pass. As seen in FIGS.10-12, each bolt 37 includes a transverse pin 41 disposed within a slot47 in the bolt 37. A release/lock plate 45 is partially disposed in theslot 47 in the bolt 37 and engages the transverse pin 41 such that thetransverse pin 41 passes through a slot 43 in the release/lock plate 45.Each bolt 37 and release/lock plate 45 may be constructed of anysuitable material, such as steel. The release/lock plate 45 includeslock detents 51 and release detents 53. When the release/lock plate 45is in a locking position, as shown in FIG. 10, one of the lock detents51 releasably engages a ball-spring mechanism 49, and the slot 43 in therelease/lock plate 45 is oriented in a direction perpendicular to thebolt 37. When the release/lock plate 45 is in a releasing position, asshown in FIG. 11, one of the release detents 53 releasably engages theball-spring mechanism 49, and the slot 43 in the release/lock plate 45is oriented in a direction parallel to the bolt 37.

In order to secure the housing halves 28, 30 together, a threaded end 55of each bolt 37 engages threads (not shown) in each lug 36 on the firsthousing half 28 and the release/lock plate 45 is placed in the releasingposition. The second housing half 30 is mated with the first housinghalf 28 such that the bolts 37 pass through the lugs 36 on the secondhousing half 30. Next, the bolts 37 are tightened until the release/lockplates 45 contact the lugs 36 on the second housing half 30. To removethe second housing half 30, the bolts 37 need be rotated only aboutone-quarter to one-half turn in order to allow the user to pivot therelease/lock plate 45 into the releasing position. Alternatively, toclamp the housing halves 28, 30 together, each bolt 37 may extend.through each lug 36 of both housing halves 28, 30 and a nut (not shown)may be used to secure each bolt 37.

Each housing half 28, 30 also includes a central bore 38, through whichthe drive shaft 24 passes, as well as four cylindrical bosses 39, whichmay be used for mounting the pump housing 26 to a support structure (notshown).

As shown in FIGS. 4 and 7, the drive shaft 24 is attached to a pair ofaxially spaced rotors 40, 42, each. preferably constructed of apolycarbonate/polyester blend. material or alternatively constructed ofa nylon material. The drive shaft 24 includes an enlarged head portion44 and a slotted portion 46. The enlarged head portion 44 has a diameterslightly larger than that of the slotted portion 46. The slotted portion46 includes an axial slot 48 disposed along the length of the slottedportion 46. Each rotor 40, 42 includes a notched hole 50 having an axialnotch 52 extending radially beyond the diameter of the notched hole 50along the axis thereof. Keys 54 fit within the axial notches 52 and theaxial slot 48 to prevent relative rotation between the drive shaft 24and the rotors 40, 42.

A pair of rollers 56 are each rotatably mounted on a roller shaft 58that is press fit into holes 59 at either end of each rotor 40, 42 andthereby secured between each rotor 40, 42. The rollers 56 may beconstructed of any suitable material. Preferably, the rollers 56 areconstructed of a self-lubricating material such as one of the followingmaterials: Vespel® SP21 material, available from E.I. DuPont De Nemoursand Company Inc., 1007 Market Street, Wilmington, Del. 19898; HYDLAR®-Z,available from A.L. Hyde Company, Grenloch, N.J. (a composite materialwith KEVLAR® fibers, available from E.I. DuPont De Nemours and Companyat the aforementioned address, embedded in a nylon matrix); NYLATRON®,available from Polymer Corporation, 2120 Fairmont Avenue, Reading, Pa.19605; MDS-filled nylon 6/6; graphite impregnated nylon; or nylonimpregnated with TEFLON®, available from E.I. DuPont De Nemours andCompany at the aforementioned address. Alternatively, separate bearings(not shown) may be mounted between each roller 56 and roller shaft 58.

A snap ring 60 engages a circumferential groove 62 in the drive shaft 24to prevent axial movement of the rotors 40, 42 with respect to the driveshaft 24. The drive shaft 24 and roller shafts 58 are preferablyconstructed from 316 stainless steel.

As best seen in FIG. 6, each housing half 28, 30 includes a crescentshaped guide block 64 disposed on the interior portion of the housinghalf 28, 30. An inwardly facing cylindrical surface 66 of the guideblock 64 defines a first perimeter portion of a rotational path of therollers 56.

A flexible tube 68 is fed through the housing 26 in a loop-shaped path,as shown in FIGS. 8 and 9. As shown by the arrows in FIG. 9, the rotors40, 42 rotate in a clockwise direction and the rollers 56 compress theflexible tubing 68 thereby causing fluid within the tubing 68 to flow ina clockwise direction through the loop-shaped path. As seen in FIGS. 8and 9, the tube 68 is disposed within the housing 26 such that first andsecond parallel portions 70, 72 overlap with one another in a regionadjacent to the guide block 64 and approximately midway between theinlet port 32 and the outlet port 34. In the region where the parallelportions 70, 72 overlap, the tube 68 is slightly compressed, such thatthe portions 70 and 72 are in forced frictional engagement with oneanother and with the housing halves 28 and 30, so as to be effectivelyclamped within the housing 26 in order to prevent the tube 68 fromcreeping through the housing 26 during operation of the peristaltic pump20. The tube 68 is clamped. tightly enough so as to prevent creep butnot to an extent that would compress the tube 68 so as to undulyrestrict the free flow of fluid though the tube 68 in the region wherethe parallel portions 70, 72 overlap.

A substantially circular wall portion 74 of the housing 26, best seen inFIG. 6, defines the loop-shaped tube path followed by the tube 68 withinthe housing 26. An outwardly facing surface 76 of the guide block 64defines a segment of the loop-shaped tube path comprising a firstperimeter portion thereof. The substantially circular wall portion 74,perimetrically spaced from the first perimeter portion of the tube path,defines a second perimeter portion of the loop-shaped tube path. Thefirst perimeter portion of the tube path, defined by the outwardlyfacing surface 76, is disposed radially outwardly of the secondperimeter portion of the tube path, defined by the substantiallycircular wall portion 74, such that the tube 68 follows a generallyelliptical path. The outwardly radial spacing, R (FIG. 9), between thefirst and second perimeter portions of the loop-shaped tube path is thedistance between the substantially circular wall portion 74 and a dashedcircle 76A having the same radius as that of the outwardly facingsurface 76.

As seen in FIG. 9, the tube 68 is compressed by the rollers 56 againstthe substantially circular wall portion 74 substantially throughout thecircular rotation path of the rollers 56, except for in the firstperimeter portion of the rotation path, in the limited region of theinwardly facing cylindrical surface 66 of the guide block 64.

To set up the peristaltic pump 20, the user removes the second housinghalf 30 and places the tube 68 in the first housing half 28 so that thetube 68 follows a loop-shaped path following the substantially circularwall portion 74 and passes around the outwardly facing surface 76 of theguide block 64. Once the tube 68 is properly placed in the first housinghalf 28, the second housing half 30 is mated with the first housing half28 using the guide posts 29 and guide holes 31 and is clamped intoposition with the quick release attachment bolts 37. Thereafter, thepump 20 may be operated simply by activating the motor 22 and thedirection of fluid flow may be reversed by reversing the direction inwhich the drive shaft 24 rotates.

Numerous modifications and alternative embodiments of the invention willbe apparent to those skilled in the art in view of the foregoingdescription. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the best mode of carrying out the invention. The details of thestructure may be varied substantially without departing from the spiritof the invention, and the exclusive use of all modifications which comewithin the scope of the appended claims is reserved.

We claim:
 1. A bolt adapted to be securely seated in a hole in an objectfor securing said object to one or more additional objects, said boltcomprising:a threaded end; a slotted end opposite said threaded end;said slotted end including a slot extending across a diameter of saidbolt and extending axially into said bolt; a release/lock plate disposedin said slot in said bolt; said release/lock plate including arelease/lock plate slot; and a pin attached to said bolt to extendtransversely through said slot in said bolt, said pin passing throughsaid release/lock plate slot to retain said release/lock plate withinsaid slot in said bolt; wherein said release/lock plate is adapted torotate about said pin between a locking position, in which saidrelease/lock plate is oriented substantially perpendicular to an axis ofsaid bolt, and a releasing position, in which said release/lock plate isoriented substantially parallel to said axis of said bolt.
 2. The boltof claim 1, further including a detent mechanism for releasablyretaining said release/lock plate in said locking position.
 3. The boltof claim 2, wherein said detent mechanism comprises a ball-springmechanism axially disposed in said bolt adjacent to said slot.
 4. Thebolt of claim 1, further including a detent mechanism for releasablyretaining said release/lock plate in said releasing position.
 5. Thebolt of claim 4, further including a detent mechanism for releasablyretaining said release/lock plate in said locking position.
 6. The boltof claim 1, further including a detent mechanism for releasablyretaining said release/lock plate in either said releasing position orsaid locking position.
 7. The bolt of claim 1, wherein said release/lockplate has a width narrower than said bolt diameter, such that saidrelease/lock plate does not extend beyond said bolt diameter when saidrelease/lock plate is in said releasing position.
 8. A peristaltic pumpfor moving a fluid through a flexible tube, comprising:a housingcomprising a pair of housing halves; a main drive shaft mounted forrotation within said housing; a rotor driven by said main drive shaftwithin said housing, said rotor having at least one roller shaftattached to said rotor, and including a roller rotatably mounted on saidroller shaft; and means for securing said housing halves to one another,said securing means including means for releasing said housing halvesfrom one another without removing said securing means or any partthereof from one of said housing halves.
 9. The peristaltic pump ofclaim 8, wherein said securing means comprises:a bolt adapted to passthrough a lug in a first housing half and adapted to be securely seatedin a lug in a second housing half, said bolt comprising: a threaded endfor engaging said lug in said second housing half; a slotted endopposite said threaded end; said slotted end including a slot extendingacross a diameter of said bolt and extending axially into said bolt; arelease/lock plate disposed in said slot in said bolt; said release/lockplate including a release/lock plate slot; and a pin attached to saidbolt to extend transversely through said slot, said pin passing throughsaid release/lock plate slot to retain said release/lock plate withinsaid slot in said bolt; wherein said release/lock plate is adapted torotate about said pin between a locking position, in which saidrelease/lock plate is oriented substantially perpendicular to an axis ofsaid bolt for engaging said lug in said first housing half whentightened, and a releasing position, in which said release/lock plate isoriented substantially parallel to said axis of said bolt for freelypassing through said lug in said first housing half.